- name
- cargo-toml-validator
- description
- Validate Rust Cargo.toml manifests for dependency issues, missing metadata, feature conflicts, workspace config, and crates.io publishing readiness. Use when validating Rust project configs, auditing dependencies, or preparing crates for publishing.
Cargo.toml Validator
Validate Rust Cargo.toml manifest files for structural correctness, dependency hygiene, feature configuration, workspace setup, and crates.io publishing readiness. Uses Python 3.11+ tomllib for native TOML parsing — no external dependencies.
Commands
validate — Full validation with all rules
python3 scripts/cargo_toml_validator.py validate Cargo.toml
python3 scripts/cargo_toml_validator.py validate Cargo.toml --strict
python3 scripts/cargo_toml_validator.py validate Cargo.toml --format json
check — Quick check (errors and warnings only)
python3 scripts/cargo_toml_validator.py check Cargo.toml
python3 scripts/cargo_toml_validator.py check Cargo.toml --format summary
explain — Show all rules with descriptions
python3 scripts/cargo_toml_validator.py explain Cargo.toml
python3 scripts/cargo_toml_validator.py explain Cargo.toml --format json
suggest — Run validation and propose fixes
python3 scripts/cargo_toml_validator.py suggest Cargo.toml
python3 scripts/cargo_toml_validator.py suggest Cargo.toml --format json
Flags
| Flag | Description |
|---|
--strict | Treat warnings as errors — exit code 1 (CI-friendly) |
--format text | Human-readable output (default) |
--format json | Machine-readable JSON |
--format summary | Compact summary with counts |
Validation Rules (24)
Structure (5)
| Rule | Severity | Description |
|---|
| S1 | error | File not found or unreadable |
| S2 | error | Empty file |
| S3 | error | Invalid TOML syntax |
| S4 | error/warning | Missing [package] section (error for bins/libs, warning for virtual workspaces) |
| S5 | error/warning | Missing required fields: name, version (error), edition (warning) |
Package Metadata (4)
| Rule | Severity | Description |
|---|
| M1 | warning | Missing edition field (defaults to 2015) |
| M2 | info | Outdated edition (2015/2018 when 2021/2024 available) |
| M3 | warning | Missing license or license-file for crates.io |
| M4 | warning | Missing description for crates.io |
Dependencies (6)
| Rule | Severity | Description |
|---|
| D1 | error | Wildcard version * |
| D2 | warning | Unpinned dependency without version specifier |
| D3 | warning | Git dependency without rev/tag/branch pin |
| D4 | info | Path dependency (blocks crates.io publish) |
| D5 | warning | Duplicate dep in [dependencies] and [dev-dependencies] with different versions |
| D6 | info | Deprecated crate name (failure, error-chain, iron, rustc-serialize, old hyper/tokio/actix-web/rocket/time) |
Features (3)
| Rule | Severity | Description |
|---|
| F1 | error | Feature enables non-existent dependency |
| F2 | warning | Empty feature (no deps or sub-features) |
| F3 | error | Circular feature dependencies |
Workspace (3)
| Rule | Severity | Description |
|---|
| W1 | warning | [workspace] with no members |
| W2 | info | Both [package] and [workspace] without members (ambiguous) |
| W3 | info | [workspace.dependencies] detected — hint about workspace = true in members |
Best Practices (3+)
| Rule | Severity | Description |
|---|
| B1 | info | Missing documentation link for published crates |
| B2 | info | Build script without [build-dependencies] |
| B3 | info | Very large number of dependencies (>30) |
| B4 | info | Missing repository/homepage URL |
Exit Codes
| Code | Meaning |
|---|
| 0 | No errors (warnings allowed unless --strict) |
| 1 | Errors found (or warnings in --strict mode) |
| 2 | File not found / parse error |
Example Output
Cargo.toml validate — Cargo.toml
=================================
[ERROR ] S5: Missing required field: package.version
Set version directly or use version.workspace = true.
[WARNING] M1: Missing edition field — defaults to 2015
Add edition = "2021" or edition = "2024" to [package].
[WARNING] D3: Git dependency 'my-fork' in [dependencies] is not pinned
Pin to a rev, tag, or branch for reproducibility. URL: https://github.com/user/fork
[INFO ] D4: Path dependency 'utils' in [dependencies] — blocks crates.io publish
Path: ../utils. Fine for local dev, but won't work on crates.io.
[INFO ] B4: Missing repository and homepage URL
Add repository = "https://github.com/..." to [package] for crates.io visibility.
Result: INVALID
Summary: 1 error(s), 2 warning(s), 2 info
